Electric Circuits - Online Test
Q1. The switch in the figure below was closed for a long time. It is opened at t = 0. The current in
the inductor of 2 H for
t ≥ 0 is
Answer : Option A
Explaination / Solution:
Q2. A load is supplied by a 230 V, 50 Hz source. The active power P and the reactive power Q consumed by the load are such that 1 kW ≤ P ≤ 2kW and 1kVAR ≤ Q ≤ kVAR . A capacitor connected across the load for power factor correction generates 1 kVAR reactive power. The worst case power factor after power factor correction is
Answer : Option B
Explaination / Solution:
Q3. The switch in the circuit has been closed for a long time. It is opened at t = 0. At t = 0+,
the current through the 1µF capacitor is
Answer : Option B
Explaination / Solution:
No Explaination.
Q4. As shown in the figure, a 1Ω resistance is connected across a source that has a load line v + i =
100. The current through the resistance is
Answer : Option B
Explaination / Solution:
No Explaination.
Q5. 
If the electrical circuit of figure (b) is an equivalent of the coupled tank system of figure (a), then
Answer : Option D
Explaination / Solution:
No Explaination.
Q6. If the 12 Ω resistor draws a current of 1A as shown in the figure, the value of resistance R is
Answer : Option B
Explaination / Solution:
No Explaination.
Q7. The two-port network P shown in the figure has ports 1 and 2, denoted by terminals (a, b) and
(c, d), respectively. It has an impedance matrix Z with parameters denoted by zij. A 1Ω resistor
is connected in series with the network at port 1 as shown in the figure. The impedance matrix
of the modified two-port network (shown as a dashed box) is
Answer : Option C
Explaination / Solution:
No Explaination.
Q8. The L-C circuit shown in the figure has an inductance L = 1mH and a capacitance
C = 10µF. 
The initial current through the inductor is zero, while the initial capacitor voltage is 100 V. The switch is closed at t = 0. The current i through the circuit is:
Answer : Option D
Explaination / Solution:
No Explaination.
Q9. The L-C circuit shown in the figure has an inductance L = 1mH and a capacitance C = 10µF. 
The L – C circuit of Q.9 is used to commutate a thyristor. Which is initially carrying a current of 5 A as shown in the figure below. The values and initial conditions of L and C are the same as in Q.9. The switch is closed at t=0. If the forward drop is negligible, the time taken for the device to turn off is
Answer : Option A
Explaination / Solution:
No Explaination.
Q10. The current through the 2 kΩ resistance in the circuit shown is
Answer : Option A
Explaination / Solution:
It is a balanced Wheatstone bridge.
